A chemically amplified positive resist composition used for semiconductor microfabrication employing a lithography process contains an acid generator comprising a compound generating an acid by irradiation.
WO 2008/99869 A1 discloses triphenylsulfonium 2-(1-adamantyl)carbonyloxy-1,1-difluoroethanesulfonate and a photoresist composition comprising triphenylsulfonium 2-(1-adamantyl)carbonyloxy-1,1-difluoroethane as an acid generator.